... -shaped Type, Steps Shaped Type(PDC coring or non-coring)MediumLimestone, marble, dolomite, rhyolite, limonite, etcSteps Shaped Type, Concentric Circles Type, Canine Tooth Shaped Type ... , Wheeling Gear Shaped TypeHardBasalt, gneiss, granodiorite, hornfels, pegmatite, etcSolid ...